Edge grinding machine



June 10, 1969 RAHRIG ET AL 3,448,547

EDGE GRINDING MACHINE Filed Dec. 2, 1965 I 25 4+- 10 2 11 0 w a :4 2

56 I I I 55 I 5 0 a,? .57 22 as 9 i INVENTORS A Tl'OK NISYA" United States Patent US. Cl. 5199 6 Claims ABSTRACT OF THE DISCLOSURE Machine for grinding the edges of plates of glass or other materials. The plates to be ground are horizontally secured on a worktable rotatable about a vertical axis and a grinding unit including a grinding wheel, also rotatable about a vertical axis, is mounted for horizontal swinging movement toward and away from the edges of the glass plates. The means for mounting the grinding unit for swinging movement includes a first horizotal arm pivoted at its outer end, a second horizontal arm secured at one end to the grinding unit and means for coupling the two arms together comprising vertical plates carried at the adjacent inner ends of said arms and angularly adjustable relative to one another about a horizontal axis to maintain the axes of rotation of the grinding wheel and worktable parallel to one another. Means for tilting the plate carrying the grinding unit vertically about said horizontal axis is also provided.

This invention relates generally to edge grinding machines and more particularly to a special mounting mechanism for the grinding wheels of such machines.

This invention constitutes an improvement over edge grinding machines such as the type shown and described in Reaser et a1. Patent No. 2,597,180, issued May 20, 1952.

In the machine shown in the aforementioned patent, the grinding wheels, drive means for the wheels and template contacting members are supported on a frame that is pivotally mounted on a swinging arm or yoke. The swinging arm is in turn mounted for swinging movement on a spindle supported above a base which also supports a rotatable worktable that is driven about an axis parallel to the spindle carrying the swinging arm. The swinging arm is urged towards the worktable to press the edges of the grinding wheels into contact with the edges of a work piece carried by the table.

However, in the machines of the above type serious difiiculties have been encountered in aligning the edges and planes of the grinding wheel with the fiat work piece to be ground. This is due for the most part because of the mass of the swinging arm or cantilever beam and the larger mass carried by the free end which includes the grinding unit and associated parts. Even assuming that the large parts could be manufactured to very close tolerances to align the various elements, experience has shown that the swinging arm may twist or deflect after short periods of use rendering the machine unacceptable for its intended purpose.

Various methods have been proposed to solve the problem of misalignment between the work piece and the grinding unit but so far as applicant is aware none have proven satisfactory.

The principal object of the present invention is to provide an improved grinding unit mounting mechanism which includes means for maintaining the axes of rotation of the grinding wheel and the work piece parallel.

Another object is to provide improved mounting means for a grinding wheel in which the grinding wheel and See the work piece are capable of being maintained in the same plane at all times.

Another object is the provision of improved mounting means for carrying grinding units which includes a coupling having movable elements intermediate the ends of the mounting means.

Other objects and advantages of the invention will become more apparent during the course of the following description when read in connection with accompanying drawings.

In the drawings, wherein like numerals are employed to designate like parts throughout the same:

FIG. 1 is a fragmentary side elevational view of an edge grinding machine having the novel features of the present invention incorporated therein;

FIG. 2 is a fragmentary horizontal sectional view taken along line 22 of FIG. 1;

FIG. 3 is a vertical sectional view taken along line 33 of FIG. 2;

FIG. 4 is a side view of the apparatus disclosed in FIG. 3;

FIG. 5 is an enlarged fragmentary end view of the apparatus disclosed in FIG. 3; and

FIG. 6 is an enlarged sectional view taken along lines 66 of FIG. 3.

Referring to FIG. 1 of the drawings, there is disclosed a fragmentary view of a portion of a grinding machine of the type shown in the above-mentioned patent and having the novel features of the present invention incorporated therein. The machine or apparatus is capable of grinding various types of work pieces such as glass plates or the like. The illustrative embodiment of the machine 10 embodying the invention includes a base 11 having a centrally located worktable 12 mounted on the upper end of a vertically rotatable spindle 13 which also carries a template 14 and serves to mount, support and rotate a work piece 15.

Although the invention is equally applicable to a single station grinding machine, a two station machine is shown in which the worktable is provided with means for carrying at least two work pieces which are held in position in spaced relation on the worktable by upper clamping plates 16 having a non-abrasive surface for engaging the work piece. The clamping plates are mounted for vertical reciprocal motion by clamping mechanisms such as air cylinders 17 carried by a strut 18 extending above the worktable with the piston rods 19 of the cylinders attached to the upper surface of the plates.

In the illustrative embodiment, two such clamping plates and cylinders are shown for clamping each of the respective work pieces against the upper surface of the worktable, with the work piece positioned in such a manner that the edges to be ground extend beyond the edge of the worktable.

While the machine embodying the invention may have one or more grinding mechanisms mounted for contacting engagement with the edge of the work piece, in the machine illustrated only one such mechanism is shown. With this arrangement, a work piece may be installed and removed at a point remote from the grinding mechanism while the table is rotating and the grinding mechanism, is finishing the edge of the second work piece clamped to the table top.

Although a single grinding unit could be provided on the grinding mechanism, two grinding units A and B are shown and each includes a grinding wheel 20 which is rotated about an axis by means, such as an electric motor 21, with the wheel directly connected to the output shaft 22 of the motor. The casing of the motor is provided with lugs having openings therein through which bolts 24 are passed with the latter received in tapped openings in a frame unit 25. The openings (not shown) in the lugs may be in the form of vertical slots to provide for vertical adjustment of each grinding unit with respect to the frame unit. The grinding unit A which is first to have grinding engagement with the edge of the work piece is for rough grinding while the second grinding unit B preferably produces a fine or finish grind.

The frame unit 25 also carries a template wheel or contractor 26 for each grinding unit which is spaced below and in axial alignment with the grinding wheel. Each of the contractors 26 is an inverted cup having a frustoconical periphery 27 and the contractor is rotatably journaled at the lower end of a J-bar 28 by suitable means (not shown). The J-bar is secured to the frame unit and mounted for vertical adjustment through securing devices 29 extending through elongated slots 30 located in the leg of the bar and received in tapped openings in the frame unit.

The template wheels are positioned in a manner to engage the rotating template mounted below the worktable. Because of the conical shape of the periphery 27 of the template contractor, if the J-bar is raised, the entire grinding unit associated therewith will be moved away from the edge of the work piece so that the finished size of the work piece ;15 is larger. Conversely, in order to compensate for wear of the grinding wheel 20, the template contractor is moved downwardly allowing the grinding unit to swing inwardly further toward the work piece. This either reduces the size of the finished work piece or compensates for reduction in the working diameter of the grinding wheel.

In the prior art devices for edge grinding, the frame unit carrying the grinding mechanism was mounted for swinging movement towards and away from the work piece by a swinging arm journaled about a pivot rod supported vertically above the base and spaced from the work piece. This arrangement made it extremely difficult, if not impossible, to align the plane of the grinding unit with the plane of the fiat work piece carried by the table if the planes were not already in alignment. This misalignment could result in part because of the size and weight of the various parts of the machine. Also, as was set forth above, the swinging arm, carrying the grinding units on the opposite free end thereof, could warp or deflect due to its size and the extreme weight carried by the free end of the arm or by changes in the position of the grinding units carried by the arm. This, of course, could result in various deficiencies of the operation of the machine since it would necessarily follow that the grinding units would not be in the exact location with respect to the work piece carried by the worktable.

However, the above deficiencies of prior art edge grinding machines are eliminated by an improved grinding unit mounting mechanism. According to the invention the mounting means includes first and second arms with one end of the first and second arms with one end of the first arm mounted for swinging movement about a fixed axis above the base of the grinding machine and one end of the second arm carrying the grinding unit. The free ends of the arms are provided with fixed elements which are part of a coupling means and are removable relative to each other to provide universal adjustment between the fixed axis of rotation of the worktable and the moving axis of rotation of the grinding wheel.

For this purpose, an I-shaped first arm 31 is supported by a pair of vertically spaced ears 32 on a pivot rod 33 with the pivot rod in turn rotatably journaled in upper and lower bearings 34 mounted in a sturdy frame upright 35 extending above the base 111. The upright is rigidified by a cross beam 36 extending crosswise and spaced above the base with the first end of the cross beam connected to the upright 35 and the second end connected toa second upright 37 extending above the base 1 1. The first arm 31 is secured in position on the pivot rod by setscrews or other securing devices (not shown) and a collar 3-8 also secured tothe pivot rod to further support the arm on the pivot rod.

The frame unit 25 carrying the grinding units is rotatably mounted on an I-shaped second arm 39 by cars 40 projecting from one surface of the frame unit having bearings 41 which rotatably receive a spindle 42 secured to one end of the second arm. The spindle may be secured to ears 43 projecting from the second arm by any suitable means.

The free ends of the first and second arms 31 and 3-9 respectively are interconnected by a coupling means, generally designated by 44, which provides for rotational and angular movement between the first and second arms.

The coupling means 44 includes a. fixed element or first plate 45 rigidly secured to the free end of the first arm 31 by any suitable means, such as a weld, with a planar surface 46 on the free side of the plate. The free end of the second arm 39 is also provided with a fixed element in the form of a second plate 48 rigidly secured thereto which has a planar surface 49 extending away from the free end of the arm.

The plate 48 is supported on the first plate 45 by a ball socket arrangement, allowing for relative angular movement with respect to each other, and means for maintaining the plate 48 in adjusted position. For this purpose, in the illustrated embodiment, a recess or opening 47 is provided in the planar surface 46 of the first plate which receives a portion of stub member 51 and is retained therein as by welding. The free portion of the stub member projecting beyond the planar surface 46 acts as a ball and is received in a recess or opening 50 in the planar surface 49 of the second plate 48. Therefore, the free portion of the stub member 51 and the recess '50 act as a ball and socket to allow for rotational and angular relative movement between the adjacent planar surfaces of the two plates.

In the illustrated embodiment, means for maintaining the plate 48 fixed in adjusted position with reference to the plate 45 includes a first set of four arcuate slots 52 and a second set of two arcuate slots 53 provided in the plate 48. The set of four slots 52 are located adjacent the upper and lower corner areas of the plate in substantially equally spaced radial relation to the horizontal axis of the stub member 51. Threaded members, such as bolts 54, are passed through the slots 52 and received in tapped holes in the plate 4 5. The two arcuate slots 53 are located in the medial area of the plate 48 at opposite sides of the stub member 51 and equally spaced therefrom. Threaded members, such as bolts 54', extend through the slots 53 and are received in tapped holes 55' in the plate 45. In this manner, the angular position of the arm 39 can be adjusted by rotary movement of the plate 48 relative to the plate 45 about the stub 51 upon loosening of the bolts 54 and 54 and thereafter maintained in adjusted position upon tightening of said bolts.

To selectively control the degree of radial adjustment of the plate 48, means are carried by the plate 45 for providing incremental rotational movement of the plate 48. This incremental adjusting means includes a pair of L-shaped brackets 56 and 56 located at the oppositely disposed upper and lower corners of the plate 45. The leg portions 57 of each bracket extend beyond the front surface 46 of the plate 45 and are disposed opposite the edges 57' of the plate 48. Pairs of bolts 58 and 58, provided with lock-nuts 59, are received in tapped holes 60 in each of the leg port-ions 57, with the inner ends of the bolts engaging the edge surfaces 57' of plate 48. In this way, after the bolts 54 and 54 have been loosened, the plate 48 can be rotated in small increments about stub member 51 by retracting the appropriate pair of bolts 58 and 58' and thereafter advancing the other pair of bolts '58 or 58', as the case may be, to angularly adjust the plate 45 either clockwise or counterclockwise relative to plate 48. It will be understood that such angular adjustment of the plate 48 will be imparted to the arm 39 and frame unit 25 relative to arm 31 to bring the grinding wheels 20 and the template wheels 26 in proper position with respect to the cam 14.

The coupling means also includes means providing for vertical tilting adjustment of the planar surface 49 of the plate 48 with respect to the planar surface 46 of plate 45. Thus, the plate 48 is adapted to be tilted upwardly or downwardly relative to the plate 45 fixed to the end of arm 31. For this purpose, pairs of bolts 61 and 62, having lock-nuts 63, are threaded into tapped holes '64 at the four corners of the plate 48, with the inner ends thereof engaging the planar surface 46 of plate 45. For example, tilting adjustment of the plate 48 can be effected by first loosening the bolts 54 and 54', and then advancing the bolt 61 so that the said bolts acting against the planar surface 46 will force the upper end of plate 48 away from plate 45. Subsequent tightening of the bolts 54 and 54' will secure the plate 48 in adjusted tilted position. Tilting of the plate 48 in the opposite direction can be effected by means of the bolts 62. The purpose of the tilting adjustments is to maintain the grinding surfaces of the grinding wheels 20 in proper relation relative to the edges of the work pieces 15.

The grinding units A and B and the mounting unit 25 are swingably urged toward the workable 12 by a suita- -ble weight 67 carried at one end of a cable 68, said cable being trained over pulleys 69 mounted by brackets 70 on the side of the frame upright 35. The opposite end of the cable 68 is connected to the first arm 31 at a point spaced from the pivot rod 33.

The operation of the machine can be readily understood with reference to FIGS. 1 and 2 of the drawings. The weight on the free end of the cable will swing the grinding units carried by the first and second arms about the pivot rod 33 to engage the template contractors 26 with the template 14 carried by the rotating spindle which also supports and rotates the worktable. This will bring the grinding units into engagement with the edge of the work piece to be ground, with the extent of grinding being determined by the location of the respective template contractors.

A work piece 15 is placed on the worktable and clamped thereto by applying air pressure to the cylinders 17 to thereby clamp the work piece on the rotating table top. The Work piece is then carried by the rotating table past and into engagement with the respective grinding uni-ts to finish the edge of the unit according to the configuration dictated by the configuration of the template 14.

Whenever it is found that the planar surface of either of the grinding wheels are not in the same plane as the planar surface of the work piece, appropriate adjustment may be made at the point of interconnection between the first and second arms by either rotating the planar surfaces of the plates, as set forth above, or by providing angular adjustment to change the angular relation of the axes of rotation of the grinding wheels and thereby have them coincide or parallel to the spindle carrying the work piece.

As can readily be appreciated, the grinding unit mounting mechanism provides a simplified means of positioning the wheels of the grinding unit or units so that their axes of rotation will be parallel to the axes of rotation of the work piece at all times.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred embodiment of the same, and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention.

We claim:

1. In a machine for grinding the edges of plates of glass or other materials, the combination of a worktable rotatable about a vertical axis, means for securing plates to be ground in a horizontal position upon said worktable for rotation therewith about said axis, a grinding unit including a grinding wheel also rotatable about a vertical axis, means for mounting said grinding unit for horizontal swinging movement to move the grinding wheel relative to the edge of the plate to be ground including a first horizontal arm pivoted at its outer end to swing horizontally and a second horizontal arm secured at its outer end to the grinding unit, and means connecting the inner end of said second arm to the inner end of said first arm for rotary movement relative thereto about a horizontal axis to maintain the axis of rotation of said grinding wheel parallel with the axis of rotation of said worktable.

2. In a machine as defined in claim 1, in which said connecting means comprises a first vertical plate fixed to the inner end of said first horizontal arm, a second vertical plate fixed to inner end of said second horizontal arm and disposed opposite said first plate, means for mounting said second plate on said first plate for movement relative thereto about a horizontal axis to angularly adjust said second plate with respect to said first plate, and means for securing the said second plate in adjusted position.

3. In a machine as defined in claim 2, in which the means for angularly adjusting said second plate comprises means carried by said first plate and engaging the said second plate.

4. In a machine as defined in claim 1, in which said connecting means comprises a first vertical plate fixed to the inner end of said first horizontal arm and having an opening therein and a second vertical plate fixed to the inner end of said second horizontal arm and having an opening therein aligned with the opening in said first plate, a stub member fixed to the first plate and projecting through the opening therein into the opening in the second plate and defining a horizontal axis about which said second plate can rotate to adjust said second plate angularly with respect to said first plate, and means for securing said second plate in adjusted position.

5. In a machine as defined in claim 4, in which the means for angularly adjusting said second plate comprises means carried by said first plate and engaging an edge of the said second plate.

6. In a machine as defined in claim 4, including means carried by one of said plates and engaging the other of said plates for tilting said second plate vertically on said stub member relative to said first plate.

References Cited UNITED STATES PATENTS 1,692,997 11/1928 Roberts 5199 2,250,448 7/ 1941 Edwards '287129 2,597,180 5/1952 Reaser 511O1 2,723,598 11/1955 Mann 5199 X 2,811,874 11/ 1957 Rethoret 51-99 X ROBERT C. RIOR'DON, Primary Examiner.

D. G. KELLY, Assistant Examiner.

US. Cl. XJR. 

